The IT company reported an adjusted profit before tax of £25.3m ($33.4m) for the six months ended 30 June. That represents a 13% decline from the same period a year ago. Total adjusted revenue was up nearly 3% to £1.5bn.
The company said a reduction in services volumes in the UK had been partly offset by strong revenue growth in Germany and France.
"Despite the challenging market conditions in the UK... as well as planned investments, the board expects the full year to show modest progress in our adjusted profit before tax," Computacenter chief executive Mike Norris said in a statement.
Revenue in the UK business fell 5% in the first half of 2016, while profits slumped nearly 40%.
"The first half of 2015 provides a tough comparison due to the exceptional volume of professional services work in 2015, which has not been repeated," Computacenter said.
"The reduction in services volumes has reduced utilisation of the group's central engines, and a consequential reduction in contractor mix used on work completed has impacted the overall margin performance."